Who wants to just watch a unicorn do magic tricks? Unicorns always do magic tricks. A PEGASUS doing magic tricks, on the other hand, is what ponies would come to see. Also, Russell just isn't in this picture.

i know,but i'm being logical,apegasus being a magcian is plain stupid,i mean,they're more athlectic or like to fly around,Unicorns have intense magic,Sunil would be a Unicorn,like Trixie,a Pegasus will never do magic tricks

Not all pegasi are athletic and like to fly. I mean, just look at Fluttershy. Unicorns only have magic related to their special talent. Sunil can't actually do magic- but he can do stage magic, which isn't even real magic like a unicorn such as Twilight could do.